<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <title>Title</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        body {
            background-color:white ;
        }
        #button {
            width: 200px;
            height: 200px;
            border: 4px solid black;
            text-align: center;
            margin: 0 auto;/*centre*/

        }
        span {
            display: block;
            color: bisque;
            font-size: 160px;
            /*border: 2px solid red;*/
        }
        input {
            /*display: none;*/
            width: 200px;
            height: 200px;
            position: fixed;
            top:0;
            opacity: 0;
        }
    </style>
</head>
<body>

    <div id="button">
        <input type="file"><!--文件接口-->
        <span>+</span>
    </div>

</body>
</html>